Power plants utilize complex machinery and systems having components that often wear out over time and require replacement. One way to mitigate catastrophic or expensive failures is to establish regular maintenance and repair schedules for critical components that are known to wear out. Sensors and instrumentation are often overlooked in the maintenance process and they are often used until failure.
Closed-loop control systems rely on accurate feedback from instrumentation to properly regulate aspects of the system being controlled. Inaccurate or non-functional instrumentation can cause undesired effects in the system, potentially leading to hardware damage and a reduction in the lifetime of parts comprising the system. Furthermore, unnecessary downtime in normally functional equipment may result from faulty instrumentation signals that trigger a protective shutdown.
The standard approach to increasing robustness to instrumentation failures has been through sensor redundancy, whereby the number of redundant sensors is increased depending on whether the measured parameter is required for monitoring, control, or safety. Such redundant systems are generally able to continue functioning when a sensor fails, but they often require human intervention to investigate the sensor and/or the failure data to determine the failure mode. In some cases, the instrumentation failure must be corrected to restore accurate feedback and optimum operation of the machinery.